Precise evaluation of bilateral pulmonary artery banding for initial palliation in high-risk hypoplastic left heart...

In patients with high-risk hypoplastic left heart syndrome (HLHS), the Norwood operation (NW) in the neonatal period still results in high mortality compared with other cardiac surgery. Bilateral pulmonary artery banding (bPAB), a very effective initial procedure for HLHS, for which the specific evaluation is as yet unsatisfactory, was performed, and we report our findings in the present study.

We have performed bPAB since 2006. A total of 17 patients with HLHS or a variant underwent bPAB before the NW. Echocardiography was performed between bPAB and the NW, and the flow acceleration just after bPAB and before NW was evaluated. Before the NW, a catheter examination was also performed.

bPAB was performed at 6.6 ± 0.6 days of age, and the NW at 130 ± 88 days. The patients' mean body weight (BW) was 2.5 ± 0.4 kg at bPAB and 4.0 ± 1.1 kg at the NW. The length of the tape for bPAB was 9.9 ± 0.6 mm in the right pulmonary artery (RPA) and 9.4 ± 0.6 mm in the left (LPA) because the RPA was usually wider than the LPA. The tape width was 2 mm in all cases. The catheter examination was performed at 95 ± 85 days after bPAB. The arterial oxygen saturation (SaO₂) was 71% ± 8.6%. Multivariate regression analysis revealed that SaO₂ was estimated well using 4 factors: the banding size of the RPA, BW at bPAB, BW at NW, and BW in the period between bPAB and catheter examination (R² = 0.79). Echocardiography just after bPAB showed that the blood flow at the bPAB had accelerated to 3.0 ± 0.8 m/s in the RPA and 3.3 ± 0.8 m/s in the LPA (P = .004). The estimated pressure gradient was 39.2 ± 17.6 mm Hg in the RPA and 46.1 ± 23.0 mm Hg in the LPA (P = .006). The blood flow at bPAB was accelerated to 3.7 ± 0.7 m/s in the RPA and 4.0 ± 0.6 m/s in the LPA before NW (P = .013). The estimated pressure gradient was 62.6 ± 27.6 mm Hg in the RPA and 56.1 ± 19.6 mm Hg in the LPA before NW (P = .014). The catheter examination revealed mean wedge pressures of 18.0 ± 7.2 mm Hg for the RPA and 16.2 ± 4.3 mm Hg for the LPA. The operative mortality rate was 0%. One patient required a repeat operation to adjust the bPAB, and prolonged pleural effusion was observed in 1 case.

The postoperative SaO₂ after bPAB correlated closely with the banding size and BW at bPAB, NW and during the period after bPAB. Because the mean PA pressure before NW was low enough for single ventricular circulation, the bPAB in this study was an effective option for high-risk patients undergoing HLHS or a variant. We believe the bPAB sizes used were suitable and were determined as follows: BW plus 7 mm for the LPA and BW plus 7.5 mm for the RPA.